This invention relates to door securing devices, and more particularly to door securing devices of the bracing type, with alarms.
With the rise in violent crimes in the United States, there is a wide spread fear among people related to their sense of security in the home and perhaps even more important, when traveling. People staying in hotels and motels often find themselves staying in a room protected only by an inexpensive lock. Many devices have been developed to provide a greater degree of protection by providing some type of portable supplemental locking devices. These devices generally fall into three main types: the portable door lock that operates with a key, as a second lock in the door; a alarm device that does not impede the operation of the door, but sounds an alarm when disturbed; and the door brace type that is mounted between the door and the floor, which then acts as a brace. The door brace can also be fitted with an alarm.
One example of the auxillary door lock is found in U.S. Pat. No. 4,059,299 to Huntly. This device is installed in the door jamb and is key operated. While this device is an effective deterrent, it is somewhat difficult to set up. Of course, if the lock is installed improperly, it will most likely fail or be difficult to remove. Also, while it is designed to fit many types of doors, it is possible that it may not fit all doors.
The second type of device is illustrated in U.S. Pat. No. 4,264,899 to Menzies, et al. This device is simply a small alarm unit that is placed against the door. If the door is moved, the device pivots and the alarm is set off. This device has the advantage of not preventing entry by emergency personnal. However, it does not prevent access by unauthorized personnel, thus, while this type of alarm is a deterrent, it will not prevent entry.
The third type of device is the most common. Several examples of this device are found in the literature. For example, U.S. Pat. No. 2,870,281 to Mitchell describes a device that is mounted on the door knob. The device is then set against the floor to prevent the door from opening. The device is provided with a pointed end that is used to keep the device from slipping when in use. The device is fitted with an alarm that will sound if the door is moved in either direction. U.S. Pat. No. 3,583,743 to Newell shows another type of brace. This device consists of a modified bumper jack. The device has a collar that fits under the door knob. It also has a small skid-proof plate mounted on the bottom to prevent slippage. The device is "jacked" into position against the door. Two other very similar devices are found in U.S Pat. Nos. 4,358,758 and 4,442,427 both to Morton. The Morton devices consist of a telescoping rod that is placed between the door knob and the floor. The bottom of the rod is fitted with a skid-proof cap. The devices use two different switching schemes for the alarms. The first patent uses a simple contact switch that is mounted at the top of the rod and placed against the door. The second device has a small alarm box with a push plunger type switch. To set this alarm, the alarm box is slid up the tube until it makes contact with the door.
All of these devices in the last catagory have one major problem: they all utilize the knob as the support point on the door. The knob is, in many cases, very weak compared to the door itself. Further, it is not designed to carry heavy loads. It is possible that the knob could fail to hold.
Many of the devices also use either small pads or no pads at all to make contact with the floor. This lack of surface contact can lead to insufficient holding strength when needed. The small pad shown in Morten can give way under repeated attempts to open the door by pushing and pulling in a rocking motion. Under this type of action, the small contact surface is insufficient to hold. It also requires the user to make sure of proper placement of the device. Otherwise, it is possible that the device will not hold at all.
The alarm device in Morton has additional problems in that it must be positioned against the door. This requires a balancing act by the user in setting the device firmly against the floor to prevent slippage, while at the same time, ensuring that the alarm switch is set properly against the door. The present invention overcomes all of these difficulties.